Portion capsule

ABSTRACT

A portion capsule includes a base element, for example like a cup, having a capsule base and a circumferential side wall. A cover element is attached to the base element and forms together with the same an interior space having an extraction material region filled with an extraction material. A filter element is placed in the interior space. The filter element separates the extraction material region from the capsule base or from a capsule cover formed by the cover element. The filter element is formed of an open pore foam material.

BACKGROUND OF THE INVENTION Field of the Invention

The invention relates to the field of systems for preparing beverages via of a liquid introduced into a beverage capsule. The invention relates particularly to a portion capsule containing an extraction material or extract, from which a beverage or beverage component can be prepared by injecting water.

Description of Related Art

Among the systems for preparing beverages, so-called coffee capsule systems are known (there are also variants for preparing tea), wherein generally hot water, typically under pressure, is introduced into a capsule in order to prepare a coffee or tea beverage by extraction. For introducing the hot water, the capsule is often pierced on one side (the injection side). Various possibilities are known for discharging the brewed beverage, generally on the other side of the capsule (the extraction side). For one, there are systems wherein piercing by means of corresponding perforation spikes is provided on the extraction side. For another, systems are known wherein a boundary of the capsule on the extraction side is pierced or torn due to interior pressure during the brewing process, to which end a means external to the capsule (present in the brewing chamber of the corresponding coffee machine) or internal to the capsule can be present. Finally, there are also already opened capsules for which no capsule wall or membrane needs to be pierced or torn in order to discharge the beverage.

In order, inter alia, to prevent ground coffee (or tea leaves) from entering the brewed beverage in an undesired manner, capsules have become known in which a filter element separating an extraction material region from a joint region and permeable to liquid in a suitable manner, for example by including a plurality of filter openings, is disposed in the interior of the capsule.

Examples of portion capsules having such filter elements are found, for example, in EP 1 344 722 and in WO 2010/085824.

A disadvantage of portion capsules having filter elements according to the prior art is that the capsules are generally produced as injection molded parts and therefore are rather complex in production and require a great deal of polymer material, having a disadvantageous effect on energy consumption in production and on the weight of the capsule. Such capsules also bring about a certain complexity in capsule design. For example, the joint product region must generally be implemented so as to receive piercing tips of the beverage preparing machine on the extraction side without said tips being damaged by impacting the filter element.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a portion capsule having a filter element and a method for producing the same. The portion capsule and particularly the filter element should be inexpensive, simple to produce, and environmentally friendly.

According to one consideration of the present invention, the portion capsule includes a base element, for example like a cup, having a capsule base and a circumferential side wall. A cover element is attached to the base element and together with the same forms an interior space having an extraction material region filled with an extraction material. A filter element is placed in the interior space. The filter element separates the extraction material region from the capsule base or from a capsule cover formed by the cover element. The filter element is formed of an open pore foam material.

Open pore or open cell foam materials refers here to foam materials wherein the walls between the pores are at least partially not completely closed, so that the foam material can receive and release liquid. The presence of closed cells—in addition to open cells—is thereby not excluded.

The foam material can be an open pore polypropylene (PP) plastic. Open pore PP foams are known from EP1479716, EP1625174, and EP2233516, for example. It has been found that open pore PP foams are particularly well suited for using as filter elements in beverage portion capsules because said foams are simple and inexpensive to produce, lightweight, temperature resistant, and recyclable. EP2233516 even discloses approaches for making such foams biodegradable.

In a further group of embodiments, the open pore foam material is made from a bio-plastic. So-called bio-plastics have already been discussed as materials for beverage capsules. Plastics produced from a renewable resource are referred to as bio-plastics (so-called bio-based plastics). Bio-plastics are also plastics able to be biodegraded (so-called biodegradable plastics). For example, biodegradable plastics for applications in the food products industry and partially including a portion of biobased plastics are known.

In the present text, “biodegradable” means biologically degradable according to the standard EN13432 (version: end of 2019), and “bio-based” means “made from renewable resources, not fossil-based.”

The material of the open pore foam material can particularly be biodegradable. It has been found that the biodegradability of foam materials made from biodegradable polymers is particularly great and advantageous. The open pore foam materials have a particularly large surface area. The organisms responsible for the biodegrading (composting) can correspondingly act over a greater surface area per volume of decomposition, and supplying with oxygen is more readily possible, for which reason the process is more efficient than for filters according to the prior art. The embodiment of the filter element made of biodegradable plastic is therefore particularly favorable and preferred for embodiments.

In one group of embodiments, the material from which the foam material is produced (such as PP or a bio-plastic) can be the same as the material of the base element and/or of the capsule cover. This combination has great advantages for recycling.

In addition or alternatively, it can be advantageous if the base element and/or cover element and the filter element are each made of a biodegradable plastic (not necessarily identical materials). This combination is also particularly favorable with respect to good recyclability.

The production of the filter element can be particularly simple. Advantage is taken of the circumstance that it is sufficient for the effectivity of the filter element that the filter element makes area contact on the radial outer side with the capsule base or capsule cover. During the brewing process, the filter element is pressed lightly against the capsule base or capsule cover due to the liquid pressure in the interior of the capsule, for which reason the filter element has a sealing effect. Very precise matching of the shape and orientation of the filter element to the capsule shape is not necessary to this end.

In some embodiments, the filter element can be produced in that a strand made of an expanded plastic is used and cut into slices. The thickness of the slices corresponds to the thickness of the filter element. Each slice then forms a filter element. The method for producing is particularly favorable and efficient. The strand can be round in cross section if the capsule has a conventional cup shape substantially symmetrical with respect to an axis. The strand can also have an approximately rectangular cross section, for example, if the capsule has a shape having a rectangular cross section, or the strand can have a different cross-sectional shape substantially adapted to the capsule shape.

A strand for producing filter elements can be produced particularly by foam extrusion. Foam extrusion is a method applicable to a series of known plastics, including bio-plastics.

The filter element can be attached to the capsule base or capsule cover in some embodiments, for example by means of welding or a suitable adhesive. In other embodiments, the filter element can also be simply placed in the base element or the cover and retained in the capsule without adhesive. The extraction material will thereby prevent the filter element from being displaced out of the provided position within the capsule during storage and transportation.

Due to the method according to the invention, it is not necessary that, in addition to an extraction material region, a joint product region, separated from the extraction material region by the filter element, into which the beverage flows and from which the beverage is discharged, is implemented in the interior of the capsule, as is provided in the prior art. Rather, due to the open pore design, the filter element itself can have a double function, in that said element not only filters but also itself forms the joint product region. Direct contact between the filter element and the capsule base or potentially the capsule cover is thus possible.

The invention further relates to an extraction system having a capsule of the type discussed and a beverage preparing machine including a brewing module into which the capsule fits. The beverage preparing machine includes in a per se known manner a water tank or a water inlet line, a water heating means, a pump, and a beverage outlet. The brewing module comprises, for example, a piercing device on the injection side and a capsule piercing and/or scoring device on the extraction side. The pump is set up for pumping water heated by the water heating means into the brewing module and thus into the capsule from the injection side. The extraction material is discharged from the capsule on the extraction side and from there reaches the beverage outlet. The brewing module and capsule shape can be mutually matched so that the filter element is present at the extraction side of the capsule.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiment examples of the invention are described below using figures. Shown are:

FIG. 1 a schematic section view of a portion capsule having the filter element and having a piercing device on each of the injection side and the extraction side;

FIG. 2 a section view of an alternative portion capsule; and

FIG. 3 a schematic view of a foam strand for producing filter elements.

DETAILED DESCRIPTION OF THE INVENTION

Identical reference numerals in the figures indicate identical or analogous elements.

The capsule 1 according to FIG. 1 includes a base element in the form of a cup 2 (having an axis 20 about which the cup is substantially rotationally symmetric, for example), and a cover element 8 attached thereto along a circumferential flange 5. The base element forms a capsule base 4 and a circumferential side wall 3, forming an outer capsule wall together with the cover 9 formed by the cover element 8 and defining a capsule interior space 7.

The cup and cover can be made of plastic in a per se known manner, for example of polypropylene (PP). The invention is also applicable, however, to capsules made of other materials, such as aluminum or paper. The cover is also attached to the cup in a known manner, for example by means of ultrasonic welding, a thermal method, or potentially by gluing.

Alternatively to a conventional plastic, the cup and/or the cover can also be made from a bio-plastic, for example Ecovio by BASF, a compound made of a biodegradable polyester (polybutylene adipate-terephthalate) and polylactide.

A filter element 2 made of an open pore (open cell) foam material is present in the capsule interior space. The filter element can be made of foamed polypropylene or a foamed bio-plastic, for example. The filter element can be simply placed in the cup and retained only by the extraction material, for example ground coffee, filling the capsule interior space. The filter element can also, however, be welded or glued or otherwise attached to the capsule base.

The material of the filter element is a foam material. The material composition can be the same as that of the capsule cup and/or of the cover element.

FIG. 1 also shows schematically a piercing device 21 on the injection side having injection-side piercing tips 22 and a piercing device 23 on the extraction side having extraction-side piercing tips 24. The piercing devices 21, 23—each having at least one piercing tip 22, 24—are present in a brewing module of a beverage preparing machine. Said piercing devices serves, as is per se known, for piercing the capsule prior to and/or during brewing, so that water can be introduced into the capsule on the injection side and the extraction material can be discharged from the capsule on the extraction side. Systems are known for which the liquid is fed through the piercing tip, as are systems for which the piercing tip merely pierces and wherein the liquid flows past the piercing tip into the capsule or out of the same. Alternatively to systems having piercing tips, systems are also known for which the capsule is ripped on the extraction side, or systems for which the capsule includes openings already prior to the brewing process, for example covered by a removable film or potentially not covered. The operating principle of the present invention is independent of how the openings for the liquid are produced.

In the embodiment example shown, the liquid is introduced into the capsule from the cover side (at the top in FIG. 1 ) and discharged out of the same through the capsule base 4, and the filter element is present on the side of the capsule base. Reverse configurations (introducing through the capsule base, discharging through the capsule cover, etc.) are also possible, however, as is also implemented in the embodiment described below, as well as configurations having a filter element on each of the two sides.

Due to the flexibility of the foam material, it is not necessary that the filter element 11 includes specific modifications at the location of contact with the corresponding piercing tip 24. The filter element can—depending on the design of the tip—yield somewhat to the tip and/or be pierced thereby.

FIG. 2 shows an alternative embodiment. This embodiment differs from the embodiment of FIG. 1 by the following features:

-   -   The shape of the capsule is not rotationally symmetric about an         axis 20, but rather the shape is as described in WO 2015/096989,         for example, having a substantially rectangular, particularly         square cross section.     -   The cover element is not implemented as a film or plate, but         rather as a three-dimensionally shaped element, for example by         means of injection molding or deep drawing. In the embodiment of         FIG. 2 , the cover element is domed, so that said element forms         a part of the circumferential side wall, as is also described in         WO 2015/096989. The actual capsule cover 9 is thus offset         outwardly from the flange 5 in the axial direction.     -   The filter element is disposed on the capsule cover and not on         the capsule base. The capsule can thus accordingly—but need         not—be matched to the brewing chamber so that the liquid is         introduced through the capsule base and discharged through the         capsule cover.

The features can be combined and implemented independently of each other. That is, a filter element can be disposed on the capsule cover for capsule shapes having a round cross section as well, a three-dimensionally shaped cover can also be combined with a round cross section and/or with disposing a filter element on the capsule base, etc.

It is also possible to apply one filter element each to both the capsule cover and the capsule base. This is advantageous particularly for embodiments for which discharging extraction material is possible not only at the extraction side but also toward the injection side and is to be prevented.

FIG. 3 shows the production of filter elements in schematic form. A strand 30 made of an extruded foam material is cut into slices forming the filter elements 11. 

1. A portion capsule comprising a base element having a capsule base and a circumferential side wall, a cover element attached to the base element and together with the base element forming an interior space having an extraction material region filled with an extraction material, and a filter element disposed in the interior space and separating the extraction material region from the capsule base or from a capsule cover formed by the cover element, wherein the filter element is formed of an open pore foam material.
 2. The portion capsule according to claim 1, wherein the base element forms a circumferential flange and the cover element is attached to the base element along the circumferential flange.
 3. The portion capsule according to claim 1, wherein the foam material is an open pore polypropylene (PP) plastic.
 4. The portion capsule according to claim 1, wherein the foam material is biodegradable.
 5. The portion capsule according to claim 1, wherein the base element and/or the cover element is made of a biodegradable plastic.
 6. The portion capsule according to claim 1, wherein a material composition of the foam material corresponds to a material composition of the base element and/or of the cover element.
 7. The portion capsule according to claim 1, wherein the filter element directly contacts the capsule base or the cover element.
 8. The portion capsule according to claim 1, wherein the filter element is produced by cutting into slices a strand made of the foam material, wherein the filter element is one of said slices.
 9. A method for producing a portion capsule according to claim 8, wherein a filter element is produced by cutting into slices a strand made of a foam material, wherein one of said slices is placed in the base element as the filter element or is attached to the cover element, the base element is filled with the extraction material, and the cover element is then attached to the base element.
 10. The method according to claim 9, wherein the strand is produced by means of foam extrusion.
 11. The method according to claim 9, wherein a same material is used as the strand material as is used for the base element and/or the cover element. 